I have a fairly simple question about the appropriate way to survey a pit.
Description of pit:
A very steep funnel shaped sink with a narrow entrance at the bottom that the caver must semi-corkscrew through to pass. After this the caver drops roughly 10 feet to a muddy ledge where the next drop below the ledge is 50-60 feet. At this point the caver is standing on another muddy, steep ledge which slopes down to a fluted well which appears to be 80-100 feet deep. At the bottom of this the caver can safely get off rope and get out of the rockfall zone.
Note: Depths are conservatively estimated but I rigged a 200 ft rope to a tree directly beside the entrance sink and all that was touching the base of the pit was my knot and 2 feet of rope.
Question:
What is the best way to delineate the depth of this pit via survey?
Any answers will be greatly appreciated. Thanks.
--Bryant